If you have a UK passport you will get the 30 day visa free waiver stamp which can be extended at your local immigration office for 30 days at a cost of ฿1,900…
you can also purchase a 60 day SETV visa for ฿1,900 in the UK then extend it for 30 days for ฿1,900 at your local immigration office…
you can also purchase the 6 month METV for ฿5,000 in the UK where I guess you have residency status or any county you have a passport for or legally recognized residency within. With strategic border bounces you can get 9 months out of the 6 month METV, but you can’t stay in country for more than 90 days at a time
You will need to purchase a 30 day extension for ฿1,900 at your local immigration office or be prepared to pay ฿500 per day of overstay…don’t get arrested, the minors Uber 18 will have no repercussions given to them
You can do a border bounce via air or land….officially there is no limit oh the amount of Air Ins one can do, however eventually you will be questioned by an overzealous immigration officer…land border crossings you get 2 per calendar year…Vietnam depending on the passport you hold you may have to buy a visa, Singapore is nice low cost airlines go to all